Field of the Invention
This invention relates to a process for preparing plates comprising a new gel polymer used alone or combined with other polysaccharides such as agar or agarose, said plates being adapted to the electrophoresis separation of the seric or plasmatic lipoproteins under a stepped gradient. Such gel polymer is fixed upon a transparent polyester film used as a mechanical support. The invention also relates to the dried and rehydratable plates obtained by this process.
It is known that the separation of human lipoproteins is carried out upon natural supports such as agar, agarose, or gelled starch, or synthetic supports such as cellulose acetate or gelled acrylamide.
In the case of supports made of agar, agarose and cellulose acetate, the electrophoretic separation shows four characteristic fractions named according to their increasing mobility: beta-lipoproteins,pre-beta-lipoproteins,alpha-lipoproteins and pre-alpha-lipoproteins.
When, in pathologic conditions there are, in the serum, micella of fatty compounds said chylomicrons, the electrophoresis normally shows a more or less noticeable trace at the beginning of the migration, said trace being revealed through liposoluble colouring reactants. In most cases however, the mechanism is more complicated. In view of their variable size, the chylomicrons are fractionated into three groups a first group localized on a line (or trace) at the starting line, a group spread between the starting line and the beta fraction and a group of a mobility substantially equal to the pre-beta-lipoproteins. The amount of said three forms differs depending on the case and above all on the support used in the electrophoresis. It is clear that such a picture is not representative of the reality, and this makes interpretation difficult, and leads to important analytical errors.
In the case of the classical supports of acrylamide and starch gel, the difficulty lies in the migration of the beta and pre-beta-lipoproteins. In fact, due to the very small size of the pores of the gel, such molecules cannot move. Attempts have been made to make possible the migration of the lipoproteins in a discontinuous gel of polyacrylamide, by decreasing to the extreme the polymer concentration. Such gels which are too soft to be handled are cast inside a small glass tube in which the electrophoretic migration is carried out. Despite rather good results, the interpretation remains difficult in view of the fact that it is impossible to obtain an accurate quantitative measure of each colored fraction by a densitometric method.